1. Field of the Invention
The present invention relates to digital telephone signaling and more particularly to a method for providing telephone subscribers with digital service.
2. Description of the Prior Art
Analog telephone lines do not use active logic at the subscriber substation and thus need power only for the telephone instrument itself. Digital supervisory signaling however requires power at the subscriber's substation at all times in order to transmit on-hook and off-hook status and in order to recognize and respond to a ring command. Thus for digital signaling power must always be presented to the line.
One approach to this problem would be to provide digital line circuits at the subscriber's premises along with analog ringers and howlers. However, this solution is expensive both in terms of circuitry and power drain.
Accordingly, it is the object of the present invention to provide a novel arrangement for extending digital service to the subscriber's premises without the requirement of digital telephones, complex digital line circuits or excessive power requirements.